Human lice (singular “louse”) are parasitic insects found on people. Adult lice are small (about 1/8 inch (3 mm) long or less) wingless insects that move by crawling. There are three species of lice that exclusively feed on humans: the head louse, the body louse, and the crab or pubic louse.

The head louse (Pediculus humanus capitis) and the body louse (Pediculus humanus humanus) are members of the same species, but the crab (pubic) louse (Pthirus pubis) is from a different insect family. All are pests of public health importance. Treatment is usually prescribed by medical professionals and should be focused on the infested person and their belongings. Use the following descriptions to...

The mere mention of head lice might make feel you itchy and start to scratch your head. However, now that children are back in school, it's a good time to talk about these tiny pests.

Although head lice can infest anyone, children are the most susceptible since they play together closely and share items that come into contact with the head like hats, headphones and combs. Head lice are not known to transmit infectious diseases and are considered more of a nuisance than a health risk. In many school districts, children with head lice are generally not allowed to attend school as long as nits are found in their hair.

An adult head louse is about the size of a sesame seed and ranges in color from tan to gray. While lice can...